php - Two Ampersands Between Function Calls

Question

What do two ampersands separating function calls do? Note: this is OUTSIDE any if statement or case statement

Like so:

functionCallOne() && functionCallTwo();

Answer 1

it is equivalent to

if ( functionCallOne() ) {
  functionCallTwo();
}

it just uses the short circuiting to make this 3 liner only take up one line